uniform mat4 mTMatrix;
attribute vec4 vPosition;
attribute float aIndex;
varying vec4 vColor;
void main() {
    gl_Position = mTMatrix * vPosition;
    if (aIndex < 0.5) {
        vColor = vec4(0.0, 1.0, 0.0, 1.0);
    } else {
        vColor = vec4(1.0, 1.0, 0.0, 1.0);
    }
}
